Effect of temperature-dependent viscosity on the entransy of both fluids in heat exchangers

In the present work,the olive oil is taken as the working fluid to demonstrate the effects of fixed viscosity and temperature-dependent viscosity on the entransy dissipation in the parallel flow heat exchangers.When the fixed value of the viscosity is larger than the average value of the temperature-dependent viscosity,the entransy dissipation with fixed viscosity is smaller than that with temperature-dependent viscosity.However,the opposite conclusion may be obtained when the fixed value of viscosity is smaller than the average value of the temperature-dependent viscosity.Under temperature-dependent viscosity condition,the smaller entransy dissipation is obtained when the hot fluid has the smaller heat capacity flow rate.The decreasing range of the entransy dissipation under fixed viscosity condition is larger than that under temperature-dependent viscosity condition as the inlet temperature of cold fluid increases.